1. Field of the Invention
The present invention relates to an image forming apparatus including an image reading device that is movable with respect to an image forming device.
2. Description of the Related Art
In an image forming apparatus including an image reading device, a plurality of cables such as a signal cable configured to transmit an image signal read by the image reading device to an image forming device and a power cable configured to supply power for driving the image reading device connects the image forming device and the image reading device. If the image reading device is movable with respect to the image forming device, the cables connect the image forming device and the image reading device while a certain degree of slack is formed in each of the cables so that the cables can be freely deformed, following movement of the image reading device.
Such a configuration is illustrated in FIG. 9A. FIG. 9A is a cross-sectional view of the image forming apparatus as viewed from the side. An image reading device 200′ is provided turnable around a rotation shaft 34′ above an image forming device 100′. A signal cable 205′ and a drive control cable 206′ connect the image forming device 100′ and the image reading device 200′. The signal cable 205′ sends an image signal from the image reading device 200′ to the image forming device 100′. The drive control cable 206′ sends power for driving the image reading device 200′ and a control signal from the image forming device 100′ to the image reading device 200′. Each of the two cables has a length sufficient to connect the image forming device 100′ and the image reading device 200′ even while the image reading device 200′ is turned to separate from the image forming device 100′. Consequently, while the image reading device 200′ is not turned with respect to the image forming device 100′, slack is formed in each of the two cables. Further, each of the two cables passes in the vicinity of the rotation shaft 34′ so that useless slack need not be formed in the cable.
Slack is thus formed in each of the signal cable 205′ and the drive control cable 206′. Therefore, an area where the two cables approach or contact each other may be formed. When the cables approach or contact each other, there may occur a phenomenon that signals respectively flowing through the cables electromagnetically interfere with each other, and noise is superimposed on the signal flowing through each of the cables, so that radiation noise generated from the cable increases.
Particularly, an amount of data transmitted through the signal cable 205′ increases with increasing reading precision and reading speed in recent years, and a frequency of the signal flowing through the signal cable 205′ is high. Thus, power of the radiation noise is high, and the signal cable 205′ electromagnetically interferes with the drive control cable 206′, so that noise easily flows through the drive control cable 206′. When the noise flows through the drive control cable 206′, the noise resonates in the apparatus main body. Thus, high-level radiation noise may be generated.
As a measure against such radiation noise, Japanese Patent Application Laid-Open No. 2002-344703 discusses a configuration in which a ground wire is arranged every other one of a plurality of bundled wires arranged parallel to one another in a flat flexible cable (FFC) to prevent radiation noise.
It is also known that radiation noise is suppressed by covering a cable with a ferrite core.